Federal and local authorities in the U.S. state of Colorado say they are investigating the background of the man charged with killing 10 people at a grocery store in Boulder this week.
Ahmad Al Aliwi Alissa was arrested Monday at the King Soopers store about 25 kilometers from his home in the city of Arvada.
A police affidavit said officers found a number of items the suspect removed at the scene of the attack, including a green tactical vest, a rifle and semiautomatic handgun, and a pair of jeans and a shirt. The document said there was “much blood around the items.”
After his arrest, officers took Alissa to the hospital for treatment of a gunshot wound to his leg.
The affidavit said investigators used a law enforcement database to determine Alissa had purchased a Ruger AR-556 pistol six days before the shooting.
The document also describes a conversation investigators had with Alissa’s sister-in-law after the shooting. She told them that in the days leading up to the shooting, Alissa had been playing with a weapon she thought looked like a “machine gun.”
The Associated Press said that according to a law enforcement official briefed on the case, Alissa’s family told investigators they believed he was suffering from some type of mental illness, including delusions. Alissa’s brother told the cable news network CNN he had become increasingly paranoid, including believing he was being followed, beginning around 2014.
Alissa’s family came to the United States from Syria, and authorities said Tuesday he had lived in the United States for most of his life.
Detective David Snelling of the Arvada Police Department said officers “had a few contacts with the suspect” during the past few years. He listed a 2017 incident at Alissa’s high school in Arvada and a speeding ticket from February of this year.
In the high school case, Alissa was convicted of assault for punching a classmate.
Alissa is due to appear in court on Thursday.